纳米多孔结构单晶硅热电薄膜声子热导率数值研究

发布时间：2018-06-17 21:57

本文选题：热电薄膜 + 纳米多孔材料　；参考：《西安交通大学学报》2017年05期

【摘要】：为降低多孔热电薄膜的热导率来提升其热电转换效率,基于离散坐标法和松弛时间近似模型求解声子Boltzmann输运方程,对单晶硅纳米多孔热电薄膜声子热导率进行了数值研究,获得了多孔硅薄膜厚度、孔隙率、边界镜面率和声子散射边界面积对其热导率的影响规律,讨论了孔隙率、多孔薄膜厚度对薄膜各向异性导热特性的影响。结果表明:随着孔隙率的增加及薄膜厚度的减小,热导率逐渐降低;当孔隙率增加到64%,且硅薄膜厚度减小到块材料硅声子平均自由程的1/10时,与块材料热导率相比,薄膜热导率至少下降两个数量级。通过分析多孔薄膜中的热流分布特性,提出了优化设计薄膜多孔结构的方法,为设计低热导率高效热电薄膜提供了理论依据。
[Abstract]:In order to reduce the thermal conductivity of porous thermoelectric thin film and improve its thermoelectric conversion efficiency, the phonon thermal conductivity of monocrystalline silicon nano-porous thermoelectric thin film was studied numerically based on discrete coordinate method and relaxation time approximation model. The influence of porous silicon film thickness, porosity, boundary specular ratio and phonon scattering boundary area on the thermal conductivity is obtained. The effects of porosity and thickness of porous film on the anisotropic thermal conductivity of the film are discussed. The results show that the thermal conductivity decreases gradually with the increase of porosity and the decrease of film thickness, and when the porosity increases to 64, and the thickness of silicon film decreases to 1 / 10 of the average free path of silicon phonon, the thermal conductivity of bulk material is higher than that of bulk material. The thermal conductivity of the film decreases by at least two orders of magnitude. Based on the analysis of heat flux distribution in porous films, a method for optimizing the porous structure of thin films is proposed, which provides a theoretical basis for the design of thermoelectric thin films with low thermal conductivity and high efficiency.
【作者单位】：西安特种设备检验检测院;西安交通大学热流科学与工程教育部重点实验室;
【基金】：高等学校博士学科点专项科研基金资助项目(20130201110042) 陕西省质量技术监督系统科研项目(2016KY01)
【分类号】：O484

【相似文献】